The present invention relates to a high frequency filter for electric instruments, and more particularly to a high frequency filter for protecting the electric instruments from inductive interference caused by various electromagnetic waves from a broadcasting station, an amateur wireless station, a civil wireless station, a personal wireless system, a military radar system and the like.
Although various high frequency filters of this kind have been proposed, reliable protection of electric instruments from inductive interference has been difficult due to insufficient band width of the filter characteristic. Meanwhile, a presently proposed high frequency filter effective in a broad radio frequency band is costly in manufacture.